Geographical Areas Of Europe Research Articles

Effect of regeneration procedures on genetic diversity in Brassica napus and B. rapa as estimated by isozyme analysis

This investigation was conducted to assess changes in the genetic structure of two varieties of two species of annual Brassica. Seeds of B. napus cv. “Topas” and B. rapa “Broccoletto” were sent to nine research institutes in different geographical areas of Europe for regeneration. The multiplied material was sent back after one year of regeneration and analysed electrophoretically. The original populations of each species and their multiplied samples were stained for 12 different enzymes, of which 4 were found to be polymorphic (DIA, SKD, GPI and PER). It was possible to detect considerable differences in isozyme patterns in B. napus and allelic frequencies in B. rapa, both within and between populations. When the original population was compared with the regenerated samples, the Chi-square homogeneity test for all pairwise comparisons revealed distinctness with a 99% probability for B. napus and 95% probability for B. rapa with one or more of the enzyme systems examined. Furthermore, the average of gene diversity analysis (Nei, 1973) revealed that some regenerated populations have less while others have increased genetic variation compared with the original population. These observations indicated that the frequencies were non-random and considerable shifts in genetic diversity have occurred during multiplication. In addition, different regeneration procedures have caused the fixation of certain alleles.

Mortality from Hodgkin's disease and other lymphomas in Europe, 1960-1990.

Trends in mortality from Hodgkin's disease (HD) and non-Hodgkin's lymphomas (NHL) in the whole of Europe and in two broad European geographic areas (Western and Eastern Europe) were reviewed over the period of 1960-1990, on the basis of official death certifications derived from the World Health Organization database. Between the early 1960s and 1990, HD mortality in the whole of Europe declined from 2.1 to 0.9/100,000 males (-58%), and from 1.1 to 0.5/100,000 (-56%) females. The decline was larger in Western Europe (around 65%), but appreciably smaller in Eastern Europe (around 30%). In contrast, mortality from NHL increased in males from 2.2 to 4.2/100,000 (+93%), and in females from 1.2 to 2.6/100,000 (+112%). These upward trends were larger in Western (over 100%) than in Eastern Europe (around 80%). The declines in HD were larger and the increases in NHL were smaller in populations below age 65. When all lymphomas were considered together, an increase was observed in both sexes (from 4.3 to 5.1/100,000 males; from 2.4 to 3.1/100,000 females) that was comparable in various areas of the continent. These data confirm a major impact of newer integrated diagnostic and therapeutic approaches in reducing HD mortality, while indicating that this impact has been delayed and limited in Eastern Europe. The upward trends in mortality from NHL probably reflect both real increases in incidence and better case ascertainment and certification, but are inconsistent with a noticeable impact of newer therapies on mortality from NHL. It is also conceivable that the introduction of immunophenotypic and immunogenotypic characterization of lymphomas has selectively eliminated from HD a worse-prognosis subset previously classified on the basis of Sternbergoid cells, which has been subsequently classified as NHL. This would have increased survival and decreased mortality from HD, while increasing incidence and mortality from NHL to an extent which is unknown but worth considering.

Protection against European isolates of tick-borne encephalitis virus after vaccination with a new tick-borne encephalitis vaccine

A highly purified, inactivated tick-borne encephalitis (TBE) virus particle vaccine has been developed. In this study we report on the efficacy of this new vaccine to protect against TBE virus isolates from different geographical areas of Europe and the Asian part of the USSR.

Interspecific mitochondrial DNA transfer and the colonization of Scandinavia by mice

SummaryRestriction enzymes were used to search for genetic variability at 162 cleavage sites in mitochondrial DNA (mtDNA) purified from 22 mice caught at seven Swedish localities. Although all of these mice bear the nuclear genes ofMus musculus, they bear the mtDNA ofM. domesticusexclusively. Yet, some of the Swedish localities are 750 km away from the hybrid zone between these two species. Furthermore, only one type of mtDNA was found at the seven Swedish localities; this type was found before at an eighth locality in Sweden as well as in Jutland north of the hybrid zone. The apparent lack of mtDNA divergence in the mouse population of Sweden contrasts with the extensive divergence usually found within other geographic areas in Europe, Africa and North America. Electrophoretic analysis of proteins encoded by nuclear genes indicates that the Swedish mice have lower average heterozygosity than Danish and Central European populations ofmusculusmice. These findings lead us to suggest that the source of the commensal mouse population in Sweden was a small propagule that originated from a population situated only a few kilometres to the east of the point at which the hybrid zone on the European mainland meets the Baltic Sea, namely on East Holstein. Such a founder event may have been associated with the spread of farming from north Germany into Sweden about 4000 years ago.

Crossing experiments with Enteromorpha intestinalis and E. compressa from different European localities

Sexual compatibility in the marine algae Enteromorpha intestinalis and E. compressa has been studied using laboratory cultures from various geographical areas in Europe. The two species are found to be totally separated by a sterility barrier. Well branched plants always fall in the same of the two genetically isolated groups and should be called E. compressa s.str., while most other plants should be referred to E. intestinalis s.l. The early development of sporophyte germlings may follow two different patterns, both of which have been observed in a single combination of parental plants, though not at the same time.

Identification of two nuclear polyhedrosis viruses from the cabbage moth, Mamestra brassicae (Lepidoptera: Noctuidae)

Two nuclear polyhedrosis viruses from the cabbage moth Mamestra brassicae found in two geographical areas in Europe have been characterized and compared. These two virus isolates have similar biological activities and have the same host range. The two M. brassicae nuclear polyhedrosis viruses can be distinguished by restriction endonuclease analysis of their DNA. They appear to be distinct but related virus strains.